A known device for detecting high-power microwave pulsed radiation can be used for establishing the fact of irradiation of an object with the specified radiation, which can result in damage to the object. Said device comprises a plate made of a conductive material and provided with one or more gaps therein. The gaps are filled with air or another dielectric. If the plate is subjected to pulsed radiation, the electromagnetic field intensity in the gaps is increased. If the field intensity exceeds the electrical strength of the dielectric in the gap, a gas-discharge breakdown occurs through the gap. The light flash that corresponds to the discharge is recorded on tape, see WO 9836286 A1.
The disadvantage of this technical solution consists in low sensitivity towards electromagnetic field (EMF) amplitude, because the EFM intensity must be quite high for the discharge to occur, since both sides of the gap have an identical original potential. Therefore EMF of moderate intensity is not recorded. In addition, the device has low sensitivity towards the incidence angle of the electromagnetic wave. When this angle deviates from the perpendicular relative to the longitudinal axis of the gaps, the sensitivity of the device is reduced to zero.
It should also be mentioned that said device only records the fact of presence or absence of the EMF and does not allow determining quantitative characteristics of the field.
Another device for measuring electromagnetic field intensity is more sensitive, said device comprising a gas-discharge chamber that is formed between electrodes separated by a dielectric. Both electrodes are cylindrical and are positioned coaxially. The cylinders are plugged on one side and positioned with the plugged ends facing outward inside a sealed dielectric envelope, wherein the ratio of diameters of the cylinders lies within the range 0.2≦d/D≦0.5, where d and D are diameters of the internal and external electrodes, respectively, see SU 1335902 A1.
Due to cylindrical shape of the electrodes, the discharge is activated by a wave that falls within the range of 360°, the moment of breakdown is recorded by measuring the intensity of current. But the discharge in the narrow gap between the cylinders occurs when the following condition is fulfilled: Uapplied field>Ubreakdown, wherein Ubreakdown=E·d, where E−field intensity, d−gap width.
Thus in order to increase field sensitivity it is necessary to reduce the gap width, however significant reduction of the gap leads to a real possibility of short circuit. Sensitivity of the known device is insufficient, because it is limited by the geometric shape of the electrodes and the minimal allowed width of the gap therebetween.
A more sensitive device for measuring electromagnetic radiation field intensity comprises a gas-discharge chamber that is formed between electrodes separated by a dielectric, where one of the electrodes is cylindrical and the other electrode is in the form of a disk, vertical symmetry axis of the cylindrical electrode is perpendicular to the disk plane, and the ratio of diameter “d” of the cylindrical electrode to the diameter “D” of the electrode in the form of a disk is in the range 0.01≦d/D≦0.3, wherein the electrodes are coupled to an electrical voltage source, and a capacitive element in the form of a pair comprising an antenna and a connection to ground is incorporated into the line coupling the cylindrical electrode to the electrical voltage source, see RU 2280258 C1.
This technical solution has been taken as a prototype of the present invention.
Incorporation of a capacitive element makes it possible to detect high-frequency components of a useful signal, because the capacitive element allows exciting electromagnetic oscillations in the electric circuit that are determined by the resonance frequency of the circuit comprising an antenna and a connection to ground.
The disadvantage of the prototype device consists in that the abovementioned circuit has a fixed resonance frequency, which does not allow detecting a useful signal in a wide range of frequencies. Besides, another disadvantage of the prototype consists in the absence of a possibility to remotely measure the electromagnetic field intensity, including its measurement in automatic mode.